JPH09217120A - Heat treatment of metallic tube - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heat treatment method for a metallic tube capable of removing the residual oil in a coiled tube at the time of heat treating a loose coil. SOLUTION: A pay-off table 1 and a receiving table 4 are rotated and the loose coil 9 on the pay-off table 1 is partly loosened to form the metallic tube 9c. While the metallic tube 9c is passed in an IH(induction heating furnace) 2 and a cooling vessel 3, the tube is taken up on the receiving table 4. In such a case, a purging gas is supplied from the other end 10b into the loose coil 9 via a purging gas supplying piping 8a, a rotary joint 7a, a conduit 11a and a joint 6a. Since the metallic tube 9c is heated to a high temp. in the IH 2, the residual oil sticking to the inside surface of the metallic tube 9c evaporates. The evaporated residual oil is pushed out by the purging gas and is discharged together with the purging gas from the one end 10a. The waste gas is cooled by a heat exchanger 41, by which the oil-component in the waste gas is condensed and the purging gas and the coil-component are separated. The oil- component is recovered into a tank 42. As a result, the residual oil in the loose coil 9 is removed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat treatment method for metal pipes used for heat exchangers of air conditioners and refrigerators, piping for construction, etc., and particularly, in the heat treatment method for removing residual oil in pipes, the process is simplified. The present invention relates to a heat treatment method for a metal tube, which can improve the heat treatment ability of a heat treatment furnace. The metal tube means a metal or alloy tube.

[0002]

2. Description of the Related Art Copper or copper alloy pipes (hereinafter referred to as copper pipes) used for heat exchangers of air conditioners and refrigerators, pipes for construction, etc. are manufactured as follows. First, an ingot is extruded, then rolled, and then subjected to rough drawing and finish drawing to obtain a metal tube loose coil. Next, in the first conventional method,
This loose coil is subjected to heat treatment (hereinafter referred to as primary heat treatment) with an induction heater (electromagnetic induction heating furnace; hereinafter referred to as IH) to obtain a metal tube loose coil annealed material, which is drawn by drawing. , The temper is set to 1 / 2H. After that, it is rolled and finished into an LWC (level wound coil) or cut into a straight pipe material to manufacture a copper pipe.

Further, in the second conventional method, a metal tube loose coil obtained by drawing is wound and finished into LWC, and this LWC is heat treated in a bright annealing furnace or the like (hereinafter, this heat treatment is referred to as secondary heat treatment). After being subjected to heat treatment to make the temper O, the product is provided as a product or is sent to a subsequent process. In the subsequent process, this LWC (annealed material) is drawn by drawing and the temper is adjusted to 1
1 / 2H, then roll finish and LWC (1 / 2H material), or after tempering is 1 / 2H, cut into straight pipe materials, and these LWC (annealed material) and straight pipe materials are It is offered as a product.

In the above-mentioned first and second conventional methods, the refining is O
Alternatively, the production method of LWC or straight pipe having 1 / 2H was for a smooth pipe. Other than smooth pipes, for example, pipes with internal grooves are manufactured by the third conventional method described below. In the third conventional method, the metal tube loose coil obtained by drawing is subjected to primary heat treatment by IH,
A metal tube loose coil annealed material is obtained and rolled to obtain an inner grooved tube. After this inner surface grooved tube is wound into LWC, secondary heat treatment is performed to make the temper O, and the product is provided as a product. Further, LWC (O material) is drawn by blanking and then rolled and finished into LWC (1 / 2H material), or after drawing by blank drawing, cutting is performed to obtain a straight pipe material (1 / 2H material).

In the typical copper pipe manufacturing process as described above, when processing such as drawing and rolling is performed, processing oil (drawing oil or rolling oil) is used, and this processing oil is used as the copper pipe. It remains inside and becomes residual oil. Residual oil causes deterioration of brazing property when a copper pipe is brazed in a subsequent process to manufacture a heat exchanger such as an air conditioner. Further, when a copper tube is used as a heat exchanger tube of a refrigerator, the tube diameter is small, so there is a possibility that the residual oil may clog the tube. For this reason,
It is necessary to remove residual oil from the inside of the pipe before supplying the copper pipe to the subsequent process.

Therefore, in the second conventional method which is a method for manufacturing a smooth tube and the third conventional method which is a method for manufacturing an inner surface smooth tube, an inert gas or the like is supplied from one end of the LWC when the LWC is subjected to the secondary heat treatment. And the residual oil is discharged to the outside of the LWC together with an inert gas (Japanese Patent Application Laid-Open Nos. 7-173523, 6-170348, and 5-772).
63 and JP-A-54-48620), or a method of absorbing residual oil by a vacuum pump from one end of LWC has been proposed.

The first conventional method will be further described. FIG.
6 to 6 are schematic diagrams showing the heat treatment method for the metal tube in the first conventional method, and FIG. 5 is a schematic diagram showing the primary heat treatment by IH. As shown in FIG. 5, payoff table 1
The bottom surface 1c has a disk shape, and an outer peripheral wall 1b is formed at the edge of the bottom surface 1c. A cylinder 1 at the center of the bottom surface 1c
a is formed. Payoff table 1 has a cylinder 1
A metal tube loose coil 9 is placed so as to surround a. Similarly, the bottom surface 4c of the receiving table 4a
Has a disk shape, and an outer peripheral wall 4b is formed at the edge of the bottom surface 4c. In addition, a cylinder 4a is provided at the center of the bottom surface 4c.
Are formed. An IH2 and a cooling bath 3 are arranged between the payoff table 1 and the receiving table 4, and the IH2 heats the metal pipe 9c during the heat treatment, and the cooling bath 3 cools the metal pipe 9c. A guide roll 31a and a straightening machine 32a are provided between the IH 2 and the payoff table 1, and the guide roll 31a advances the metal tube loose coil 9 to the straightening machine 32a side to correct the straightening machine 3a.
Insert smoothly into 2a. A straightener 32b and a bending roll 33a are provided between the cooling tank 3 and the receiving table 4, and the straightener 32a is a straightener 32.
Similar to b, the metal pipe 9c is straightened and smoothly advanced in the traveling direction, and the metal pipe 9c is guided to the bending roll 33a. The bending roll 33a changes the direction of the metal tube 9c so that the metal tube 9c can be smoothly and sequentially formed in the narrowing coil shape on the lasing table 4.

In the apparatus configured as described above, the payoff table 1 and the receiving table 4 are rotated, and the loose coil 9 on the payoff table 1 is started to be wound on the receiving table 4. Then, since the loose coil 9 is heated to a high temperature in the IH2, the IH
Annealing (primary heat treatment) is applied to the metal tube 9c in the second tube 2. After that, the metal tube 9c passes through the cooling tank 3 and is then wound around the receiving table 4 by the bending roll 33a so that the traveling direction of the metal tube 9c becomes the direction of the lasing table 4. After such annealing is performed over the entire area of the metal tube 9c, the loose coil 9 moves from the payoff table 1 to the receiving table 4 and becomes the loose coil 9f.

Next, the metal tube of the loose coil 9f is finished. FIG. 6A is a schematic diagram showing a finishing device. As shown in FIG. 6 (a), the guide roll 31 b, the die 81, and the drawing machine 62 are guided along the traveling method of the metal pipe 9 d.
And the straightener 32c is arrange | positioned. Guide roll 31
b supports the metal tube 9d, and the die 81 is a drawing machine 62.
The metal tube 9d is evacuated by the driving force of. Straightener 32
For c, the position of the metal tube 9d is appropriate.

In the finishing device constructed as above,
The metal tube 9d is drawn by the die 81 by the driving force of the drawing machine 62 to be reduced in diameter, and the temper is halved.
H. Further, as shown in FIG. 6A, the bending direction of the metal tube 9d is changed by the bending roll 33b, and the metal tube 9d is wound up by an appropriate driving device to become the LWC 61. As shown in FIG. 6B, the metal pipe 9d may be cut by the cutting machine 34 after passing through the drawing machine 62 to be a straight pipe material 35. The obtained straight pipe material 35 is placed on the outlet table 36.

Next, the second conventional method will be further described. FIG. 7 is a schematic diagram showing winding finish. 7, the same components as those in FIG. 5 or 6 are designated by the same reference numerals, and detailed description thereof will be omitted. As shown in FIG. 7, the metal tube loose coil 9 is placed on the payoff table 1.
This loose coil 9 is subjected to finishing processing to become LWC61.

Next, the LWC 61 is annealed (secondary heat treatment) in a bright annealing furnace. FIG. 8 is a schematic view showing the steps of the secondary heat treatment. As shown in FIG. 8, the bright annealing furnace is composed of an inlet side vestibule 25a, a heating zone 26, a cooling zone 27 and an outlet side vestibule 25b. Entry side vestibule 25
a is a room that prevents the atmosphere from entering the heating zone 26, and the outlet vestibule 25b is a room that prevents the atmosphere from entering the cooling zone 27. The LWC 61 is annealed in the heating zone 26 after passing through the entrance side vestibule 25a, cooled in the cooling zone 27, passed through the exit side vestibule 25b, and sent out of the bright annealing furnace. In this case, L
Purge gas is supplied to the WC 61. FIG. 9 shows LW
It is a schematic diagram which shows the connection state of C61 and the conduit 76 for purge gas supply. As shown in FIG. 9, LW is performed in the bright annealing furnace.
C61 is placed on the roller 74 via a tray 75. One end 76 a of the LWC 61 is one end 6 of the conduit 76.
0a and the other end 76b of the conduit 76 is connected to the joint 7
It is connected to the gas pipe 77 via 2. Also conduit 76
Is the winder 7 existing between the gas pipe 77 and the LWC 61.
The length of the conduit 76 can be adjusted by turning the winder 73 according to the distance between the gas pipe 77 and the LWC 61. An inert gas (nitrogen gas or the like) is constantly supplied to the LWC 61 from the conduit 76 while the bright annealing furnace is in progress. As shown in FIG. 8, the LWC 61 is the heating zone 2
When entering 6, the residual oil in the LWC 61 is vaporized, and the residual oil is discharged out of the LWC 61 together with the inert gas supplied from the conduit 76.

FIG. 10 is a schematic diagram showing how LWC61 (annealed material) is drawn to obtain LWC61a (1 / 2H material). 10, the same parts as those in FIG. 6 are designated by the same reference numerals, and detailed description thereof will be omitted. As shown in FIG. 10A, the payoff table 37 is supported by a support base 46 via support rods 45. Further, in the center of the payoff table 37, the axis of the LWC 61 (annealed material) and the axis of the payoff table 37 are coaxial with each other.
The pillar 38 is formed. After being annealed in the bright annealing furnace, LWC61 (annealed material) is
7. Next, the LWC61 (annealed material) is evacuated by the die 81 to have its diameter reduced and the temper becomes 1 / 2H, and then it is wound up to obtain the LWC61a (1).
/ 2H material). In addition, as shown in FIG.
It is also possible to empty the WC 61 (annealed material) and then cut it by the cutting machine 34 to obtain the straight pipe material 35. The obtained straight pipe material 35 is
It is placed on the delivery table 36.

Next, the third conventional method will be further described. In the third embodiment, first, as in the first embodiment,
The metal tube loose coil 9 shown in FIG. 5 is subjected to primary heat treatment with IH2 to obtain a metal tube loose coil 9f. Next, the obtained metal tube loose coil 9f is rolled. FIG. 11 is a schematic diagram showing rolling of a metal tube loose coil. 11, the same parts as those in FIG. 5 are designated by the same reference numerals, and detailed description thereof will be omitted. As shown in FIG. 11, the obtained metal tube loose coil 9 f is placed on the payoff table 1. Next, the loose coil 9f is linearly unrolled to form a metal tube 9e, which is rolled by a rolling machine 39 and then rolled into a loose metal tube loose tube (tube with inner groove) 9f.

Next, as shown in FIG. 6, the metal tube coil 9
F (inner grooved tube) is wound and finished to obtain LWC61.
Next, as shown in FIG. 8, this LWC 61 is annealed by performing a secondary heat treatment in a bright annealing furnace. During this annealing, the residual oil can be removed by supplying the purge gas into the LWC 61 as in the second conventional method. The obtained LW
C61 (annealed material) is provided as a product. Further, as shown in FIG. 10, this LWC 61 (annealed material) was subjected to a blanking process with a die 81 and then wound up to obtain an LWC.
It may be 61a (1 / 2H material). FIG. 6 (b)
As shown in, the straight pipe material 35 may be obtained by performing a blanking process with the die 81 and then cutting.

[0016]

However, the above-mentioned conventional method has the following problems. That is, in the first conventional method, as shown in FIG. 5, after drawing to obtain the loose coil 9, the loose coil 9 is extended to form the metal tube 9c, and this metal tube 9c is subjected to the primary heat treatment in IH. ,
In this primary heat treatment, there is a problem that there is no method for removing the residual oil in the metal tube 9c.

Further, in the second conventional method, the residual oil is removed when the LWC 61 is subjected to the secondary heat treatment in the bright annealing furnace. However, since the time required for removing residual oil is longer than the time required for secondary heat treatment (annealing), residual oil removal is not completed even when heat treatment is completed, and residual oil removal is completed. Until bright annealing furnace to LWC
I can't take out 61. Therefore, there is a problem that the processing capacity of the heat treatment furnace is reduced by 10 to 50%.

Further, in the third conventional method, as shown in FIG. 11, a rolling oil is used in order to apply the inner groove processing to the metal pipe 9e. Therefore, in addition to the drawn oil, the rolled oil is LWC6.
1 will remain. Such an LWC61
As shown in FIG. 8, when the secondary heat treatment is performed to anneal and the residual oil in the pipe is removed, the residual oil amount in the pipe is much larger than that in the second conventional method. In addition, it will take more time to remove the residual oil. Therefore, the third conventional method has a problem that the processing capacity of the heat treatment furnace is further reduced as compared with the second conventional method.

The present invention has been made in view of the above problems, and it is possible to remove the residual oil in the coil tube during the heat treatment of the loose coil, without lowering the treatment capacity of the heat treatment in the subsequent step. Another object of the present invention is to provide a heat treatment method for a metal tube, which can omit the manufacturing process.

[0020]

According to a first heat treatment method for metal pipes of the present invention, a metal pipe unwound from a metal pipe coil placed on a payoff table is continuously heat-treated by passing through a heating furnace. After that, in the heat treatment method of the metal pipe wound on the receiving table, a residual gas in the metal pipe is removed by blowing a purge gas into the metal pipe being heat-treated from the pipe end of the metal pipe coil on the receiving table side. And

In this case, it is preferable that oil is recovered from the gas discharged from the pipe end of the metal pipe coil on the payoff table side.

In the second heat treatment method for a metal tube according to the present invention, a metal tube unwound from a metal tube coil placed on a payoff table is continuously heat-treated through a heating furnace, and then a receiving table is used. In the heat treatment method for the metal tube to be wound up, a purge gas is blown into the metal tube being heat-treated from the tube end of the metal tube coil on the payoff table side to remove residual oil in the metal tube.

In this case, it is preferable that oil is recovered from the gas discharged from the pipe end of the metal pipe coil on the receiving table side.

In the third heat treatment method for a metal tube according to the present invention, the metal tube unwound from the metal tube coil placed on the pay-off table is continuously heat-treated through a heating furnace, and then the receiving table is placed. In the heat treatment method for a metal tube to be wound up, a purge gas is blown into the metal tube being heat-treated from the tube end of the metal tube coil on the payoff table side, and then the heat treatment is performed from the tube end of the metal tube coil on the receiving table side. The residual oil in the metal pipe is removed by blowing the purge gas into the metal pipe.

In this case, when the purge gas is blown from the pipe end of the metal pipe coil on the payoff table side, oil is recovered from the gas discharged from the pipe end of the metal pipe coil on the receiving table side. When blowing the purge gas from the pipe end of the metal pipe coil of the receiving table, it is preferable to recover oil from the gas discharged from the pipe end of the metal pipe coil on the payoff table side.

In any heat treatment method for metal tubes,
It is preferable that both ends of the metal tube coil are closed after the heat treatment of the entire metal tube is completed.

In any of the heat treatment methods for metal tubes, the purge gas may be an inert gas, the purge gas may be a reducing gas, and the purge gas may be dry air. Also, the purge gas may be silicone oil.

Further, the metal tube coil placed on the payoff table may be either a loose coil or a tight coil. Similarly, the coil obtained by winding the receiving coil may be either a loose coil or a tight coil.

Furthermore, the heating furnace may be an electromagnetic induction furnace, a resistance heating furnace or a gas furnace.

In the heat treatment method of the metal tube according to the first aspect, the metal tube coil is unwound while blowing the purge gas from the tube end of the metal tube coil on the receiving coil side, and a part of the metal tube coil is formed into a linear metal tube. The metal tube is heat treated. Then, the temperature of the metal tube becomes high during the heat treatment, so that the residual oil adhering to the inside of the metal tube is vaporized. Therefore, the vaporized residual oil is discharged as exhaust gas together with the purge gas from the pipe end of the metal pipe coil on the opposite side. As a result, residual oil in the metal tube coil is removed.

When the heating furnace has a heating zone and a cooling zone, since the purge gas is blown from the pipe end of the metal tube coil on the receiving table side, the purge gas passes through the metal tube in the cooling zone and then in the metal tube in the heating zone. To reach. This purge gas purges the vaporized residual oil, and the residual oil is discharged from the pipe end together with the purge gas without passing through the metal pipe in the cooling zone. Therefore, there is an advantage that the residual oil is not recondensed.

Further, when the residual oil vaporized by the purge gas is discharged from the pipe end on the payoff table side, the vaporized residual oil is cooled if the length of the metal tube of the metal tube coil on the payoff table side is long. Recondenses in the metal tube. However,
Even in this case, since the metal tube of the metal tube coil on the payoff table side eventually passes through the heating furnace, even if recondensation occurs in the metal tube at the payoff table, the recondensed residual oil is vaporized again and purge gas is used. Since it is pushed back to the payoff table side, recondensation is not a problem. Further, as the heat treatment progresses, the length of the metal tube of the metal tube coil on the payoff table side becomes shorter, so that the vaporized residual oil is discharged without being recondensed.

In the heat treatment method for a metal tube according to claim 3, from the tube end of the metal tube coil on the payoff table side,
While blowing the purge gas, the metal tube coil is unwound to form a linear metal tube, and the metal tube is heat-treated. Then, similar to the heat treatment method for a metal pipe according to claim 1, since the metal pipe becomes high temperature during the heat treatment, the residual oil adhering to the inside of the metal pipe is vaporized. Therefore, the vaporized residual oil is discharged as exhaust gas together with the purge gas from the pipe end of the metal pipe coil on the opposite side. As a result, residual oil in the metal pipe is removed.

When the heating furnace has a heating zone and a cooling zone, the purge gas is blown from the tube end of the metal tube coil on the payoff table side. Therefore, the purge gas passes through the metal tube of the heating zone and then inside the metal tube of the cooling zone. To reach. As described above, when the purge gas reaches the inside of the metal pipe in the heating zone after passing through the inside of the metal pipe in the cooling zone, if the purge gas has a high temperature, the cooling efficiency of the metal pipe in the cooling zone decreases. On the other hand, after the purge gas has passed through the metal pipe in the heating zone,
If the purge gas reaches the inside of the metal pipe in the cooling zone, preheating the purge gas can improve the residual oil removal efficiency without reducing the cooling efficiency in the cooling zone.

In the heat treatment method for a metal tube according to a fifth aspect, first, the metal tube coil is unwound while blowing the purge gas from the tube end of the metal tube coil on the pay-off table side, and a part of the metal tube coil is formed into a linear metal. A tube is formed, and this metal tube is heat-treated. When the length of the metal tube coil on the payoff table side and the length of the metal tube coil on the rasiving table side become substantially equal, the pipe end for blowing the purge gas is changed from the pipe end on the payoff table side to the pipe end on the rasiving table side. Instead, the metal pipe is heat-treated while blowing the purge gas from the pipe end of the metal pipe coil on the lasing table side. Then, the distance between the metal tube and the tube end from which the gas is discharged is always half or less of the entire length of the metal tube, which is shorter than the above-mentioned heat treatment method for the metal tube. Therefore, it is possible to prevent the exhaust gas, especially the residual oil, from recondensing in the pipe. As a result, the efficiency of removing residual oil is improved as compared with the heat treatment methods for metal pipes according to claims 1 and 3.

In any heat treatment method for metal tubes,
Exhaust gas is discharged from the pipe end. By recovering oil from the exhaust gas, it is possible to prevent the outer surface of the metal pipe from being contaminated with the exhaust gas, and also to prevent air pollution. Further, by closing both pipe ends of the metal pipe with a cap or the like after the heat treatment, residual oil is removed and the inner surface of the metal pipe, which is easily oxidized, can be protected from oxidation by the atmosphere or the like.

The purge gas in the present invention is preferably a gas that can remove residual oil efficiently and that does not cause the inner surface of the metal tube to be oxidized or discolored. Examples of such a gas include an inert gas, a reducing gas, dry air, and silicone oil. Dry air can be used for aluminum or aluminum alloy tubes and the like. Silicon oil adheres to the inside of the metal pipe and functions as a lubricant when bending or expanding the metal pipe in a later step, and also as a rust preventive agent.
Alternatively, a purge gas may be prepared by mixing silicon oil with an inert gas, a reducing gas or dry air.

The method for heat treating a metal tube of the present invention is mainly used for a metal tube made of copper or a copper alloy, but is not limited to this, and other metals or alloys such as a metal tube made of aluminum or an aluminum alloy. It can be applied to the metal tube.

[0039]

BEST MODE FOR CARRYING OUT THE INVENTION Next, an embodiment of the present invention will be described.
This will be specifically described with reference to the accompanying drawings. FIG. 1 is a schematic view showing a heat treatment method for a metal tube according to the first embodiment of the present invention. 1, the same parts as those in FIG. 5 are designated by the same reference numerals, and detailed description thereof will be omitted. The bottom surface 1c of the payoff table 1 has a disk shape, and the outer peripheral wall 1 is provided at the edge of the bottom surface 1c.
b is formed. A column 1a is formed at the center of the bottom surface 1c. A loose coil 9 is placed on the payoff table 1 so as to surround the column 1a. Further, a notch 21a is formed in the longitudinal direction of the column 1a, and a joint 6b is formed on the upper surface of the column 1a.

FIG. 2 is an enlarged view showing the bottom surface 1c of the payoff table 1. The outer peripheral wall 1b is omitted for clarity of the bottom surface 1c. As shown in FIG. 2, a recess 44 is formed on the bottom surface 1c. One end 10a of the loose coil advances in the recess 44 from the outer peripheral wall 1b side toward the notch 21, further rises in the notch 21a, and is connected to the joint 6b. By connecting the one end 10a of the loose coil to the joint 6b in this manner, the one end 10a of the loose coil 9 does not come into contact with the loose coil 9 and the loose coil 9 is not scratched by the one end 10a. The joint 6b is connected to the flexible pipe 11b,
b is connected to the rotary joint 7b. Rotary joint 7b
Is connected to a blower 24 via a conduit 23a, and the blower 24 is connected to a heat exchanger 41 via a conduit 23b. Below the heat exchanger 41, a tank 42
Is arranged. As a result, the exhaust gas is at one end 10a
After being discharged from the flexible pipe 11b, the rotary joint 7
b is supplied to the blower 24 via the conduit 23a. The exhaust gas is supplied to the heat exchanger 41 by the blower 24,
It is cooled by the heat exchanger 41. As a result, the residual oil component in the exhaust gas is condensed, the exhaust gas is separated into the purge gas and the residual oil, and the condensed residual oil is accumulated in the tank 42. On the other hand, the purge gas is supplied to the conduit 23c and collected.

The bottom surface 4c of the receiving table 4 has a disk shape, and an outer peripheral wall 4b is formed at the edge of the bottom surface 4c. A column 4a is formed at the center of the bottom surface 4c. An IH 2 and a cooling tank 3 are arranged between the payoff table 1 and the receiving table 4.
During the heat treatment, part of the loose coil 9 is released and the metal tube 9c
And IH2 heats the metal tube 9c for heat treatment. The cooling tank 3 cools the metal tube 9c after the heat treatment. A joint 6a is formed on the side surface of the column 4a, and a rotary joint 7a is installed above the column 4a. Joint 6
a is connected to the rotary joint 7a via a flexible pipe 11a, and the rotary joint 7a is connected to the purge gas supply pipe 8a.
It is connected to the. A notch 21b is formed in the column 4b, and like the payoff table 1, the rasiving table 4 is also provided with a recess on its bottom surface 4c.
The other end 10b of the loose coil 9 passes through the IH 2 and the cooling tank 3 to reach the receiving table 4, and then the bottom portion 4c.
Of the outer peripheral wall 4b toward the notch 21b,
Further, the notch 21b is raised and connected to the joint 6a. The recess and the notch 21 prevent the loose coil 9 from being scratched by the other end 10b. As a result, during the heat treatment, the purge gas is supplied from the other end 10b into the loose coil 9 through the purge gas supply pipe 8a, the rotary joint 7a, the flexible pipe 11a and the joint 6a. Note that nitrogen gas is usually used as the purge gas, and the pressure thereof is not particularly limited, but is about 0.5 to 50 atm.

In the apparatus constructed as described above, the payoff table 1 and the receiving table 4 are rotated, and the loose coil 9 on the payoff table 1 starts to be wound on the receiving table 4. Then, since the loose coil 9 is heated to a high temperature in the IH2, the residual oil attached to the metal tube 9c is vaporized. The vaporized residual oil is pushed out to the purge gas, and is
The exhaust gas is exhausted from the exhaust pipe 0a
b, the rotary joint 7b, the conduit 23a, and the blower 24 to reach the heat exchanger 41. Next, the exhaust gas is the heat exchanger 4
1, the oil component in the exhaust gas is condensed, the purge gas and the oil component are separated, and the oil component is recovered in the tank 42.
Thus, the vaporized residual oil can be removed by the purge gas by sequentially performing the heat treatment with IH2 while winding the metal tube 9c on the receiving table 4. Further, by collecting the oil content by the tank 42, it is possible to prevent the outer surface of the loose coil 9 from being contaminated and prevent the air pollution.

Since the purge gas is supplied from the other end 10b of the loose coil on the receiving table 4 side,
The purge gas passes through the metal tube 9c of the cooling tank 3 and then IH2
It reaches the inside of the metal tube 9c. When the length of the metal tube of the loose coil 9 on the payoff table 1 is long, the vaporized residual oil is cooled and recondensed in the metal tube. However, even in this case, the metal tube of the loose coil 9 on the payoff table 1 side eventually passes through IH2, so that the payoff table 1 is not removed.
Even if re-condensation occurs in the metal pipe of the loose coil 9 at, the re-condensed residual oil is vaporized again. The vaporized residual oil is
The purge gas moves to the one end 1a side. Therefore, it does not reach the cooling tank 3. Further, as the heat treatment progresses, the length of the metal tube of the loose coil 9 on the payoff table 1 side becomes shorter, so the vaporized residual oil is discharged from the end 10a without recondensing. In this way, the purge gas purges the residual oil, and the residual oil reaches the one end 10a without passing through the metal pipe 9c of the cooling tank 3. Therefore, the residual oil does not re-condense in the metal pipe 9c of the cooling tank 3, so that the amount of residual oil in the pipe can be extremely reduced.

When the residual oil is removed from the loose coil 9 in this manner, there is no oil for protecting the inner surface of the loose coil 9, so that the inner surface of the loose coil 9 is easily oxidized and discolored. In order to prevent this oxidation and discoloration, it is preferable that after the residual oil is removed, caps are fitted to the one end 10a and the other end 10b of the loose coil 9 to prevent atmospheric air from entering the loose coil 9. Although dry air can be used as the purge gas in this embodiment, inert gas, reducing gas, silicone oil, or the like can also be used depending on the type of the loose coil 9.

As shown in FIG. 6, the loose coil 9 thus obtained is wound and finished to form an LWC (metal tube coil) 61, or cut to form a straight tube material 35. Served as.

Next, a second embodiment of the present invention will be described. FIG. 3 is a schematic view showing a heat treatment method for a metal tube according to the second embodiment of the present invention. 3, the same parts as those in FIG. 1 are designated by the same reference numerals, and detailed description thereof will be omitted. As shown in FIG. 3, in the second embodiment, the blower 24, the heat exchanger 41 and the tank 42 are arranged on the cylinder 4a of the receiving table 4, and the purge gas is supplied on the cylinder 4a of the payoff table 1. A pipe 8b is installed.

In the apparatus configured as described above, the payoff table 1 and the receiving table 4 are rotated, and the loose coil 9 on the payoff table 1 starts to be wound on the receiving table 4. Then, since the metal pipe 9c is heated to a high temperature in the IH2, the residual oil attached to the metal pipe 9c is vaporized. The vaporized residual oil is pushed out by the purge gas, exhausted from the other end 10b together with the purge gas, and the oil content is recovered from the exhaust gas in the tank 42.

Thus, the vaporized residual oil can be removed by the purge gas by sequentially heat-treating the metal tube 9c with IH2 while winding the loose coil 9 on the receiving table 4. As a result, the same effect as that of the first embodiment is obtained. Further, the purge gas is the metal tube 9 of IH2.
After passing through the inside of c, it reaches the inside of the metal pipe 9c of the cooling tank 3. That is, the purge gas does not pass through the cooling tank 3 before the IH2. Therefore, even if the purge gas is at a high temperature, the cooling efficiency of the cooling tank 3 does not decrease, and the residual oil removal efficiency can be improved by preheating the purge gas in advance.

Next, a third embodiment of the present invention will be described. FIG. 4 is a schematic view showing a heat treatment method for a metal tube according to the third embodiment of the present invention. 4, the same parts as those in FIGS. 1 and 3 are designated by the same reference numerals, and detailed description thereof will be omitted. As shown in FIG. 4A, in the third embodiment,
A forked pipe 23d is connected to the rotary joint 7b of the cylinder 1a of the payoff table 1, and a valve 43a is connected to one end of the forked pipe 23d. A purge gas supply pipe 8b is connected to the valve 43a. On the other hand, the forked tube 23
The other end of d is connected to a conduit 23a via a valve 43b, and the blower 24 and the heat exchanger 41 are connected to the conduit 23a in the same manner as in the first embodiment so that the purge gas and the residual oil in the exhaust gas Is separated and the oil is collected. Further, by providing the valves 43a and 43b, the purge gas can be supplied to the one end 10a by opening the valve 43a and closing the valve 43b. On the other hand, by closing the valve 43a and opening the valve 43b, the exhaust gas can be collected from the one end 10a.

On the other hand, a bifurcated tube 23d is connected to the rotary joint 7a of the lacing table 4 as in the payoff table 1. Similar to the payoff table 1, a valve 43c and a valve 43d are connected to the forked pipe 23d, and the valve 43c is connected to the purge gas supply pipe 8a. The valve 43d is connected to the blower 24 via the conduit 23a, and the blower 24 is connected to the conduit 23.
It is connected to the heat exchanger 41 via b. Heat exchanger 4
A tank 42 is disposed below 1 to collect the oil content in the exhaust gas. By providing the valves 43c and 43d, the purge gas can be supplied to the other end 10b by opening the valve 43c and closing the valve 43d. On the other hand, if the valve 43c is closed and the valve 43d is opened, the exhaust gas can be collected from the other end 10b.

In the apparatus constructed as described above, first, the valves 43a and 43d are opened and the valves 43b and 43c are closed. Next, the payoff table 1 and the receiving table 4 are rotated, and the loose coil 9 on the payoff table 1 is moved to the receiving table 4.
Start winding on. Then, in the IH2, the metal tube 9c
Is heated to a high temperature, the residual oil adhering to the inside of the coil 9 is vaporized. The vaporized residual oil is pushed out by the purge gas and exhausted from the other end 10b together with the purge gas, and the oil content in the exhaust gas is recovered in the tank 42.

Next, when the length of the loose coil 9a on the payoff table 1 and the length of the loose coil 9b on the receiving table 4 become substantially equal, the valve 43 is released.
a and 43d are closed, and valves 43b and 43
Release c. After switching the valves in this way, the metal pipe 9 is supplied from the other end 10b into the loose coil 9 through the purge gas supply pipe 8a, the rotary joint 7a, the flexible pipe 11a and the joint 6a.
Resume winding of c. Then, the vaporized residual oil is
Extruded by the purge gas, and the end 10a together with the purge gas
Is exhausted from the tank and collected in the tank 42. in this way,
In the middle of removing residual oil, set the purge gas supply port to one
Since the distance from the IH2 to the tank 42 can be shortened by switching from 0a to the other end 10b,
It is possible to prevent the exhaust gas from re-condensing in the loose coil 9. Thereby, in addition to the same effects as those of the first and second embodiments, the efficiency of removing residual oil can be improved.

[0053]

EXAMPLE Next, the result of actually removing the residual oil in the pipe of the metal pipe coil by the method of the first embodiment will be described in comparison with a comparative example.

First Embodiment In the method of the first embodiment , as shown in FIG. 1, the residual oil in the loose coil 9 was removed when the loose coil 9 was subjected to the primary heat treatment in IH2. On the other hand, in the comparative example method, residual oil was removed by the second conventional method shown in FIG.

In each of the examples and the comparative examples, the material of the loose coil is phosphorus deoxidized copper, the outer diameter of the loose coil is 800 to 3000 mm, and the weight of the coil is 8 mm.
It was set to 0 to 500 kg. In the embodiment, IH is used as the annealing furnace, and the heating temperature of IH is 500 to 700 ° C.
The residual oil in the pipe was removed at a feed rate of 120 to 500 m / min. Further, in the comparative example, a bright annealing furnace is used as the annealing furnace, and the heating temperature of the bright annealing furnace is 450 to 70.
The residual oil in the tube was removed at 0 ° C.

As a result, the amount of residual oil in the loose coil pipe is
In each of the example method and the comparative example method, as shown in Table 1 below, it was 0.1 mg / m or less. However,
The processing capacity of the heat treatment furnace in the comparative example method was reduced by about 30% as compared with the processing capacity of the heat treatment furnace in the example method. That is, the method of the embodiment can significantly improve the productivity while maintaining the amount of residual oil in the pipe at the same level as the conventional one.

When the residual oil treatment is not applied to the metal tube coil as in the first conventional method, the residual oil amount in the tube is about 3 mg /
This is an extremely large amount of m.

[0058]

[Table 1]

Second Example A loose coil 9 made of a phosphorus deoxidized copper tube was prepared. The outer diameter of the phosphorous deoxidized copper pipe is 12.7 mm, the wall thickness is 0.37 mm,
The total length is 2037m. The loose coil 9 was heat-treated under the conditions of a feed rate of 200 m / min, a purge gas of nitrogen, a purge gas pressure of 4 kg / cm ² , and a drawn oil viscosity of 500 centistokes to remove residual oil in the tube of the loose coil 9. . 16 sampling points were selected at equal intervals along the longitudinal direction of the phosphorus deoxidized copper tube of the loose coil 9. A copper pipe having a length of 10 m was sampled so as to include the sample ring point, the residual oil was recovered from the copper pipe, and the residual amount of the residual oil was measured. As a result, the maximum amount of residual oil in the pipe was 0.10 mg.
/ M, minimum value 0.01mg / m, average value 0.04m
It was g / m, and the heat treatment could be carried out while maintaining the residual oil amount in the pipe at a low amount.

[0060]

As described above, according to the heat treatment method for a metal pipe according to the first aspect, the purge gas is blown into the metal pipe from the pipe end of the metal pipe coil on the receiving table side to remove the residual oil in the metal pipe. Since it is removed, the productivity of the metal pipe can be improved, and the vaporized residual oil can be prevented from being recondensed.

Further, according to the heat treatment method for a metal pipe according to the third aspect, since the purge gas is blown into the metal pipe from the pipe end of the metal pipe coil on the payoff table side, the residual oil in the metal pipe is removed. Productivity can be improved. Further, when the heating furnace has the heating zone and the cooling zone, the purge gas reaches the cooling zone after passing through the heating zone, so that it is possible to prevent the cooling efficiency of the cooling zone from being lowered by the heat of the purge gas.

Further, according to the heat treatment method of the metal tube of the fifth aspect, after the purge gas is blown into the metal tube from the tube end of the metal tube coil on the payoff table side, the metal tube coil on the receiving table side is blown from the tube end. By blowing the purge gas into the metal pipe to remove the residual oil in the metal pipe, it is possible to improve the productivity of the metal pipe and prevent the recondensation of the residual oil gas to improve the residual oil removal efficiency. be able to.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing a heat treatment method for a metal tube according to a first embodiment of the present invention.

FIG. 2 is an enlarged view showing a bottom surface 1c of the payoff table 1.

FIG. 3 is a schematic diagram showing a heat treatment method for a metal tube according to a second embodiment of the present invention.

FIG. 4 is a schematic diagram showing a heat treatment method for a metal tube according to a third embodiment of the present invention.

FIG. 5 is a schematic view showing a primary heat treatment by IH.

FIG. 6 is a schematic view showing winding finish.

FIG. 7 is a schematic view showing winding finish.

FIG. 8 is a schematic view showing a step of secondary heat treatment.

FIG. 9 is a schematic diagram showing a connection state of an LWC 61 and a purge gas supply conduit 76.

FIG. 10 is a schematic view showing an emptying process.

FIG. 11 is a schematic view showing rolling of a metal tube loose coil.

[Explanation of symbols]

 1, 37; payoff table 1a, 4a; column 1b, 4b; outer peripheral wall 1c, 4c; bottom surface 2; IH (electromagnetic induction heating furnace) 3; cooling tank 4; receiving table 6a, 6b; joint 7a, 7b; rotary joint 8a, 8b; Purge gas supply pipe 9, 9a, 9b, 9f, 9g; Loose coil 9c, 9d, 9e; Metal pipe 10a; One end 10b; Other end 11a, 11b; Flexible pipe 21a, 21b; Cutout 23a, 23b, 23c , 76; conduit 23d; bifurcated tube 24; blower 25a; inlet side vestible 25b; outlet side vestibule 26; heating zone 27; cooling zone 31a, 31b; guide roll 32c; straightening machine 33b; bending roll 34; cutting machine 35; Straight pipe material 36; Delivery side table 38; Support post 39; Rolling machine 41; Heat exchanger 42; Tanks 43a, 43 , 43c, 43d; valve 44; recess 45; supporting bar 46; support platform 61 and 61a; LWC 62; pulling machine 72; joint 73; winder 74; roller 75; trays 77; gas pipe 81; dice

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Takashi Kuriyama 1-8-2 Marunouchi, Chiyoda-ku, Tokyo Incorporated company Kobe Steel, Ltd. Tokyo headquarters (72) Inventor Riki Ashida 65 Hirasawa, Hadano, Kanagawa Prefecture Co., Ltd. Inside the Hadano Plant of Kobe Steel

Claims (11)

[Claims] 1. A heat treatment method for a metal tube wound on a receiving table after continuously heat-treating a metal tube unwound from a metal tube coil placed on a pay-off table through a heating furnace. A heat treatment method for a metal tube, characterized in that a residual gas in the metal tube is removed by blowing a purge gas into the metal tube being heat-treated from the end of the metal tube coil on the side. 2. The heat treatment method for a metal pipe according to claim 1, wherein oil is recovered from the gas discharged from the pipe end of the metal pipe coil on the payoff table side. 3. A heat treatment method for a metal tube unwound from a metal tube coil placed on a payoff table, which is continuously heat-treated through a heating furnace and then wound on a receiving table. A heat treatment method for a metal tube, characterized in that a residual gas in the metal tube is removed by blowing a purge gas into the metal tube being heat-treated from the end of the metal tube coil on the side. 4. The heat treatment method for a metal pipe according to claim 3, wherein oil is recovered from the gas discharged from the pipe end of the metal pipe coil on the receiving table side. 5. A heat treatment method for a metal tube wound on a receiving table after a metal tube unwound from a metal tube coil placed on the payoff table is continuously heat-treated through a heating furnace and then wound on a receiving table. After blowing a purge gas into the metal pipe being heat-treated from the pipe end of the metal pipe coil on the side, the purge gas is blown into the metal pipe being heat-treated from the pipe end of the metal pipe coil on the receiving table side to the metal. A method for heat treating a metal tube, which comprises removing residual oil in the tube. 6. When blowing the purge gas from the pipe end of the metal pipe coil on the payoff table side, oil is recovered from the gas discharged from the pipe end of the metal pipe coil on the receiving table side, 6. When the purge gas is blown from the pipe end of the metal pipe coil of the receiving table, oil is recovered from the gas discharged from the pipe end of the metal pipe coil on the payoff table side. A heat treatment method for a metal tube as described. 7. After finishing the heat treatment of the entire metal tube,
7. The heat treatment method for a metal pipe according to claim 1, wherein both pipe ends of the metal pipe coil are closed. 8. The heat treatment method for a metal tube according to claim 1, wherein the purge gas is an inert gas. 9. The heat treatment method for a metal tube according to claim 1, wherein the purge gas is a reducing gas. 10. The heat treatment method for a metal tube according to claim 1, wherein the purge gas is dry air. 11. The heat treatment method for a metal tube according to claim 1, wherein the purge gas is silicon oil.